This invention pertains generally to infrared (IR) seekers, and particularly to a high g hardened, strapped-down seeker intended for use as the sensor in a cannon-launched spin-stabilized guided projectile.
A guidance system for a spinning projectile is described in U.S. Pat. No. 4,347,996 issued Sept. 7, 1982 to V. A. Grosso and assigned to the same assignee as this application.
As is known, IR seekers have been extensively utilized in such applications as air-to-air missiles and anti-armor submunitions. IR seekers, however, have not found broad application as the sensors for cannon-launched projectiles because of the difficulty inherent in withstanding the "high g" environment, usually around 17,000 g's, experienced with a cannon launch. The problem of g-hardening the IR seeker is two-fold in that both the gimbal system for the optical telescope and the IR dome must survive the high g environment. A first approach to g-hardening the gimbal system utilizes a mechanism for restraining the gimbal system during launch and releasing the gimbal system after launch. This approach is relatively complex, expensive and of questionable reliability. A second approach to g-hardening the gimbal system utilizes a gimbal system in the form of an optical-free gyroscope supported on a noncompliant lined spherical gas bearing. While this design has survived a launch environment on the order of 10,000 g's, further refinements and improvements are required to enable this design to withstand a 17,000 g load.
Generally, for optical considerations a hemispherical IR dome is utilized on IR seekers and the g-hardening of such domes to withstand the anticipated launch environment has proven to be a difficult task.